Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
manh hai » lanh hai, minh hai, thanh hai
thac tuc » thac toc, thai tuc, thach thuc
su sach » so sach, vu sach
va manh » van manh, va danh, va hanh
hieu va » lieu va, hieu qua
su viet » so viet
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano
te sach » toc sach
tuc va » thuc va, truc va, tuc xa
hai su » hai vu, lai su, hai so

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (te sach)) tu nang xa hoi. ((hieu van) OR (hieu va)) thac tuc va manh hai su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (te sach)) tu nang xa hoi. ((hieu van) OR (hieu va)) thac tuc va manh hai su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (te sach)) tu nang xa hoi. ((hieu van) OR (hieu va)) thac tuc va manh hai su viet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (te sach)) tu nang xa hoi. ((hieu van) OR (hieu va)) thac tuc va manh hai su viet*.